In general, database users view databases from computer equipment. This computer equipment is provided with a display screen on which users can read the data that they need.
However, database users would very frequently like to keep essential information in an easily transportable form.
There are printers than can be associated with computer equipment to obtain printouts of all or some of data displayed on display screens. These large paper printouts (A4 size) are not convenient to transport in clothes pockets. Obviously, it would be possible to fold them but in this case the information would no longer be quickly and easily accessible. The paper would have to be unfolded.